Step-by-step switch



STEPBY*STEP SWITCH ors Sheet Filed Sept. 14, 1966 FIG. 7.

April 22, 1969 w. GERSPACH STEPBY STEP SWITCH Sheet Filed Sept. 14, 1966April 22, 1969 w. GERSPACH 3,440,582

STEP-BY-STBP SWITCH Filed Sept. 14. 1966 Sheet 3, or 3 FIGS.

United States Patent Int. or. n0ih51/08, 9/54 U.S. Cl. 335-438 6 ClaimsABSTRACT OF THE DISCLOSURE A magnetically operated Stepping switchwherein the switching member comprises a turnable spring-biased solenoidcore arranged for both rotary and axial movement. The core has a radialpin alternately engagebale with opposed cam teeth to effect its rotarymovement as it is axially reciprocated by energization anddeenergization of the solenoid. Magnetic blocking members normally blockthe core against axial movement, and are shifted to unblock the core bythe flux of the solenoid.

This invention relates to step-by-step switches based on the plungerarmature principle, in which the switch drive utilises the tractivepower of a plunger armature in a magnet coil through which currentpasses, and in which the switch movement is effected by means of a pinwhich is firmly inserted radially in the extended plunger armature andthe axial movement of the plunger armature is limited by two crownratchet wheels, the common axis of which is constituted by the plungerarmature. In this type of switching drive the pin is pulled out of thebutton of the tooth of the first ratchet wheel by the traction of theplunger armature and comes to bear against the opposite tooth flank ofthe second ratchet wheel, on which it slides away in a rotary movement.After collapse of the magnetic field the pin drops back into the nexttooth bottom of the rest ratchet wheel and thereby performs a completeswitching step which is equivalent to an angular movement correspondingto the tooth pitch.

In known step-by-step switches of this type, external forces producingmechanical accelerations in the axial direction or accelerations havingcomponents in that direction undesirably produce a step movement.

An object of the present invention is to achieve the effect thatmechanical accelerations due to external forces on the step-by-stepswitch in any direction cannot give rise to a movement step. Ontermination of the action of such an acceleration the conditon of theswitch which previously existed remains in effect. By means of theinvention this is achieved by a blocking device, through the fact thatadditional magnetic locking means are disposed in the magnetic flux pathof the plunger armature magnet, in such a manner that on thecommencement of the build-up of the magnetic field for the plungerarmature they are drawn out of the path of movement of the plungerarmature or out of the path of movement of locking elements joined tothe plunger armature before, 0n the further build-up of the magneticfield, the plunger armature itself is attracted.

If the step-by-step switch according to the invention is not energizedmagnetically but simply accelerated mechanically, as by external forceswith a component in the axial direction, the plunger armature is heldlocked against axial movement and thus cannot advance the stepby-stepswitch.

One embodiment of the invention will now be exice plained in greaterdetail, with reference to the accompanying drawings, in which:

FIGURE 1 illustrates the construction of a step-bystep switch in theposition of rest;

FIGURE 2 illustrates the switch with armature attracted; and

FIGURE 3 illustrates two toothed end face parts which are disposedopposite but offset in relation to one another. In the toothingillustrated, for the sake of simplicity the opposite toothing is notshown as a pair of teeth;

FIGURE 4 illustrates the switch in a view from above.

Referring to the drawings a step-by-step switch consists of an ironmagnet shell 1, a coil 2, a plunger armature 3, a cross-pin 4, and twoend face crown toothings or gear wheels 5 and 6. In accordance with thisinvention 1 provide an improved armature blocking means which isautomatically releasable, comprising slide bolts in the form of lockingmagnet pieces 7 and 8 with restoring springs 9 and 10, and a locking potor cup 11 with a restoring spring 12. The stepping switch furthercomprises contact springs 13 and 14 which are movable with the plunger3, and a stationary supply contact pin 15, with a stationary separateoutput contact pin 16 for each step.

When current is applied to the coil 2, it builds up around it a magneticfield through the magnetic circuit which includes the iron magnet shellI and also the flux conducting mountings 1a, 1b which constitute slidebearings for the locking magnet pieces 7, 8, as well as the lowerannular pole piece 10 which field first attracts the locking magnetpieces 7 and 8 toward the plunger armature 3. As the magnetic fieldbecomes stronger, the plunger armature 3 experiences its operationalmovement and is drawn downward into the coil 2. Since, according to theinvention, the locking magnet pieces 7 and 8 have been drawn inward andaway from the sliding region of the locking pot 11, the latter can allowthe downward movement of the plunger armature and thus the crosspin 4strikes against the corresponding tooth pair of the crown toothing 5(FIGURES 2 and 3). Through the force applied the cross-pin moves out ofposition 17 of the crown toothing 6 which is illustrated in FIGURE 3 andinto the position 18 of the crown toothing 5, so that the plungerarmature turns by half a tooth.

In FIGURE 2 this attracted condition of the step-bystep switch isillustrated. When the coil 2 is now deprived of current, the plungerarmature drops back into its position of rest under the action of therestoring spring 12. The cross-pin thus passes from position 18 (FIGURE3) of the crown toothing 5 to position 19 of the crown toothing 6. Theplunger armature has thus performed the second half of the rotary stepby sliding on the tooth flank. The two locking magnet pieces 7 and 8 arebrought again into the starting position by the action of the springs '9and 10.

Through the above cycle the supply contact pin 15 (FIGURE 1) has nowbeen connected through the two contact springs 13 and 14 to the nextcontact pin 16 which follows by one step the previously connectedcontact pin 16.

Through further electric impulses the step-by-step switch can be movedon one step at a time.

If a previously adjusted step-by-step switch of the present type isexposed only to a mechanical acceleration as from external forces, thecontact springs 13, 14 cannot be advanced, because the two lockingmagnet pieces 7 and 8 lie in the sliding region of the locking pot 11and thus block and prevent the plunger armature 3 from moving downwardinto the coil 2, so that the cross-pin 4 remains locked between thetooth breast 20 and the tooth flank 21 (FIGURE 3) which prevent rotationof the plunger armature and therefore of the contact springs the plunger13 and 14. On termination of the action of any mechanical accelerationhaving axial components, even if the contact springs 13 and 14 haveduring such acceleration been lifted off the contact pins 15 and 16 ofthe previously adjusted step, said springs will again bear against thesecontact pins so that a perfect contact is ensured. If it is desired toensure that the constacts 15, 14: 13, 16 will not be opened even underthe action of an axial acceleration, the contact springs 13 and 14 havesimply to be constructed with a larger spring path than the free axialmovement play of the plunger armature 3 in relation to the lockingmagnet pieces 7 and 8.

This free movement play or lost motion of the plunger armature 3 can forexample be'seen in FIGURE 1 as the distance between the bottom edge ofthe locking pot 11 and the locking magnet pieces 7 and 8.

The mechanical locking between the locking magnet pieces and the lockingpot may be constructed differently from the construction describedabove. It is however essential that through the build-up of the magneticfield for the plunger armature the mechanical locking should bereleased.

I claim:

1. A shock and acceleration resistant electrically-operated electricstepping switch comprising, in combination:

(a) a driving magnet coil,

(b) a plunger armature acted on by flux from said coil and movablebetween a first, non-attracted position and a second, attractedposition,

(c) a cross pin afiixed to the armature,

(d) armature drive means comprising opposed sets of cam teethalternately engageable by said cross pin as the armature is movedbetween said first and second positions, for efiecting a stepped rotarymove- (a) a cup aifixed to the armature and movable axially therewith,

(b) magnet pieces movable toward and away from the armature andattracted toward the latter by magnetism thereof,

(c) spring means urging the said pieces away from the armatures and intothe path of movement of said p,

((1) said magnetism overcoming the spring means and shifting the magnetpieces out of said path of movement.

3. The invention as in claim 2, wherein:

(a) at least two, oppositely disposed magnet pieces are provided,cooperable with said cup.

4. The invention as in claim 2, wherein:

(a) the blocking means further includes flux-conducting slide bearingscarrying said magnet pieces and connected to the magnetic circuit forthe magnet coil.

5. The invention as in claim 4, wherein:

(a) said magnet pieces comprise slide bolts movable in radial directionwith respect to said armature.

6. The invention as in claim 1, wherein:

(a) the armature has some lost motion between its first position and itsblocked position,

(b) said armature carrying contact springs,

(c) fixed contacts cooperable with said contact springs and engageabletherewith when the armature is in said first position,

(d) said springs having an inherent path of spring movement which isgreater than said lost motion movement of the armature, and being soconstituted that they normally remain in contact with said fixedcontacts at all times that the armature remains blocked or in its firstposition.

References Cited UNITED STATES PATENTS 8/1964 Griggs 335174 2/1966Ostrander 335--l39 US. Cl. X.R. 335--l74

